Abstract:
An information about ‘elastika’-forms is presented. These forms have been mathematically described by Euler in the middle of the 18th century. Some of these forms correspond to the strongly-nonlinear waves propagating in different media. Examples of wave equations describing elastica-like waves are presented. Special attention is given to the nonlinear Klein-Gordon equation. The exact and approximate solutions to this equation are constructed. These solutions describe some elastica-like travelling waves. They can also describe a formation of strongly-localized wave objects in some resonators. It is stressed that these objects (particles, bubbles) can occur during the origin of the Universe and affect its subsequent evolution.